Due to bandwidth demands resulting from increasing demands for various services, for example, voice, data, and multimedia, from human beings, an Optical Transport Network (OTN) increasingly becomes a core network for carrying services of each operator.
When the OTN network is widely applied, it is necessary to map services of various rates to a high rate Optical Channel Transport Unit (OTU) network for transporting, and it is necessary to de-map the high rate OTUk to obtain multiple paths of low rate services. Sizes of an OTUk (k is 1, 2, 3, or other natural numbers) frame are consistent, but a frame rate is increased as k is increased. In the prior art, a multiplexing and mapping form of an OTN is defined, differences between OTUk and OTUj clocks are compensated by setting positive justification opportunity (PJO) and negative justification opportunity (NJO) bytes in a frame structure of the high rate OTU, so as to realize conversion between OTN signals of different rate levels. When the low rate OTUj data is recovered by de-mapping, an asynchronous clock of the OTUj needs to be recovered from a high rate OTUk clock. In the prior art, justification is performed through the PJO and NJO bytes, that is, clock information is delivered through the PJO and NJO bytes.
During the implementation of the present invention, the inventor finds that the prior art at least has the following disadvantages. In the prior art, the mapping is implemented by adopting the PJO and NJO bytes, and information represented by the PJO and NJO bytes is limited, so that multiplexing and mapping to the OTN network can be performed on services of only a small part of rate levels, and de-mapping can also be performed on service data of only a small part of rate levels, and thus multiplexing and mapping and de-mapping cannot be implemented on the services of various types in the existing network.